Monolithic Composite Blade and Platform

ABSTRACT

A component for a gas turbine engine. The component includes a continuous fiber blade including an airfoil extending radially between a root and a tip and a blade attachment feature positioned at or adjacent to the root. The component further includes a platform coupled to the root of the continuous fiber blade. The platform includes a plurality of chopped fibers. Additionally, the component includes a thermoplastic polymer contained in both the continuous fiber blade and the platform. Moreover, the continuous fiber blade and platform are coupled together such that the continuous fiber blade and platform form a monolithic composite body.

FIELD

The present subject matter relates generally to monolithic compositecomponents and, more particularly, to monolithic composite blades andplatforms for gas turbine engines.

BACKGROUND

A gas turbine engine generally includes a fan and a core arranged inflow communication with one another. Additionally, the core of the gasturbine engine generally includes, in serial flow order, a compressorsection, a combustion section, a turbine section, and an exhaustsection. In operation, air is provided from the fan to an inlet of thecompressor section where one or more axial compressors progressivelycompress the air until it reaches the combustion section. Fuel is mixedwith the compressed air and burned within the combustion section toprovide combustion gases. The combustion gases are routed from thecombustion section to the turbine section. The flow of combustion gasesthrough the turbine section drives the turbine section and is thenrouted through the exhaust section, e.g., to atmosphere.

The compressor section of the gas turbine engine typically includes anumber of airfoils or blades attached to a rotor of the gas turbineengine. Further, the compressor section generally includes platformspositioned between the airfoils in order to define an inner boundary forthe air provided from the fan section to the inlet of the compressor.Accordingly, at least some known gas turbine engines include airfoilsand platforms formed separately and removably coupled together andattached to the rotor of the gas turbine engine. However, suchairfoil-platform assemblies require additional process steps in order tocouple the airfoils and platforms together, such as secondary bonding orfastening. Additionally, sealing may be required between the componentsof the airfoil-platform assembly. Further, such sealing may includeleaks that reduce the efficiency of the gas turbine engine.

As such, there is a need for an airfoil-platform assembly that enables areduction in the number of process steps and an increased efficiency ofa gas turbine engine.

BRIEF DESCRIPTION

Aspects and advantages will be set forth in part in the followingdescription, or may be obvious from the description, or may be learnedthrough practice of the invention.

In one aspect, the present subject matter is directed to a component fora gas turbine engine. The component includes a continuous fiber bladeincluding an airfoil extending radially between a root and a tip and ablade attachment feature positioned at or adjacent to the root. Thecomponent further includes a platform coupled to the root of thecontinuous fiber blade. The platform includes a plurality of choppedfibers. Additionally, the component includes a thermoplastic polymercontained in both the continuous fiber blade and the platform. Moreover,the continuous fiber blade and platform are coupled together such thatthe continuous fiber blade and platform form a monolithic compositebody.

In an additional embodiment, the continuous fiber blade may define apressure side and a suction side. Further, the platform may be coupledto the pressure side or suction side of the continuous fiber blade. Inanother embodiment, the platform may include two platforms. A firstplatform may be coupled to the pressure side of the continuous fiberblade, and a second platform may be coupled to the suction side of thecontinuous fiber blade. In another embodiment, the platform may includea split platform defining a notch such that the continuous fiber bladeis received within the notch and coupled to the split platform at thenotch.

In another embodiment, the continuous fiber blade may be formed, atleast in part, by molding of a continuous fiber thermoplastic composite.In a further embodiment, the platform may be formed, at least in part,by at least one of compression molding or injection molding of theplurality of chopped fibers. In one such embodiment, the platform may becoupled to the continuous fiber blade via injection molding at aninterface between the platform and the continuous fiber blade. Inanother such embodiment, the platform may be coupled to the continuousfiber blade simultaneously with the molding of the platform. In afurther embodiment, the thermoplastic polymer may include a bondinglayer between the continuous fiber blade and the platform. In a stillfurther embodiment, the thermoplastic polymer may include at least oneof PEKK, PEEK, PAEK, or PEI.

In another aspect, the present subject matter is directed to a gasturbine engine defining a centerline. The gas turbine engine includes anengine shaft extending along the centerline, a compressor attached tothe engine shaft and extending radially about the centerline, acombustor positioned downstream of the compressor to receive acompressed fluid therefrom, and a turbine mounted on the engine shaftdownstream of the combustor to provide a rotational force to thecompressor. The gas turbine engine further includes a monolithiccomposite component connected to the engine shaft. The monolithiccomposite component includes a continuous fiber blade including anairfoil extending radially outward from a root to a tip and a bladeattachment feature positioned at or adjacent to the root. The monolithiccomposite component further includes a platform coupled to the root ofthe continuous fiber blade. The platform includes a plurality of choppedfibers. Additionally, the monolithic composite component includes athermoplastic polymer contained in both the continuous fiber blade andthe platform. Moreover, the continuous fiber blade and platform arecoupled together such that the continuous fiber blade and platform forma monolithic composite body.

In one embodiment, the gas turbine engine may include a plurality ofmonolithic composite components. In such an embodiment, a portion of themonolithic composite components may be arranged circumferentially aboutthe centerline to form a stage. In one such embodiment, the platforms ofeach of the plurality of monolithic composite components may extend atleast partially in a circumferential direction relative to thecenterline. Further, the platform of at least two adjacent monolithiccomposite components of the portion of the monolithic compositecomponents may define a butt joint therebetween in the circumferentialdirection. It should be further understood that the gas turbine enginemay further include any of the additional features as described herein.

In another aspect, the present subject matter is directed to a method offorming a monolithic composite component for a gas turbine engine. Themethod includes molding a continuous fiber thermoplastic composite intoa continuous fiber blade including an airfoil extending radially outwardfrom a root to a tip and a blade attachment feature positioned at oradjacent to the root. The method additionally includes forming aplurality of chopped fibers into a platform containing a thermoplasticpolymer. Further, the method includes coupling the platform to the rootof the continuous fiber blade such that the platform and continuousfiber blade form the monolithic composite component.

In one embodiment, forming the plurality of chopped fibers into theplatform may include at least one of compression molding or injectionmolding of the chopped fibers. In another embodiment, coupling theplatform to the root of the continuous fiber blade may include utilizinginjection molding at an interface between the platform and thecontinuous fiber blade. In a still further embodiment, coupling theplatform to the root of the continuous fiber blade may includesimultaneously coupling the platform to the continuous fiber blade whilemolding the platform. It should be further understood that the methodmay further include any of the additional features as described herein.

These and other features, aspects and advantages will become betterunderstood with reference to the following description and appendedclaims. The accompanying drawings, which are incorporated in andconstitute a part of this specification, illustrate embodiments of theinvention and, together with the description, serve to explain certainprinciples of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appended FIGS.,in which:

FIG. 1 illustrates a cross-sectional view of one embodiment of a gasturbine engine that may be utilized within an aircraft in accordancewith aspects of the present subject matter, particularly illustratingthe gas turbine engine configured as a high-bypass turbofan jet engine;

FIG. 2 illustrates one embodiment of a monolithic composite componentfor a gas turbine engine in accordance with aspects of the presentsubject matter, particularly illustrating two monolithic compositecomponents arranged circumferentially about a centerline to form astage;

FIG. 3 illustrates an exploded perspective view of an exemplarymonolithic composite component in accordance with aspects of the presentsubject matter, particularly illustrating the monolithic compositecomponent including a blade and platforms;

FIG. 4 illustrates an exploded perspective view of an alternativeexemplary monolithic composite component in accordance with aspects ofthe present subject matter, particularly illustrating a blade and asplit platform;

FIG. 5 illustrates another view of an exemplary monolithic compositecomponent in accordance with aspects of the present disclosure,particularly, FIG. 5 illustrates a partially exploded view of themonolithic composite component where one platform is separated from ablade while another platform is shown monolithically formed to theblade; and

FIG. 6 illustrates a flow diagram of one embodiment of a method offorming a monolithic composite component for a gas turbine engine inaccordance with aspects of the present disclosure.

Repeat use of reference characters in the present specification anddrawings is intended to represent the same or analogous features orelements of the present invention.

DETAILED DESCRIPTION

Reference now will be made in detail to embodiments of the invention,one or more examples of which are illustrated in the drawings. Eachexample is provided by way of explanation of the invention, notlimitation of the invention. In fact, it will be apparent to thoseskilled in the art that various modifications and variations can be madein the present invention without departing from the scope of theinvention. For instance, features illustrated or described as part ofone embodiment can be used with another embodiment to yield a stillfurther embodiment. Thus, it is intended that the present inventioncovers such modifications and variations as come within the scope of theappended claims and their equivalents.

As used herein, the terms “first”, “second”, and “third” may be usedinterchangeably to distinguish one component from another and are notintended to signify location or importance of the individual components.

The terms “upstream” and “downstream” refer to the relative directionwith respect to fluid flow in a fluid pathway. For example, “upstream”refers to the direction from which the fluid flows, and “downstream”refers to the direction to which the fluid flows.

The terms “coupled,” “fixed,” “attached to,” and the like refer to bothdirect coupling, fixing, or attaching, as well as indirect coupling,fixing, or attaching through one or more intermediate components orfeatures, unless otherwise specified herein.

The terms “communicate,” “communicating,” “communicative,” and the likerefer to both direct communication as well as indirect communicationsuch as through a memory system or another intermediary system.

A monolithic composite component for a gas turbine engine and associatedmethods for forming the same are generally provided. The component mayinclude a continuous fiber blade including an airfoil extending radiallybetween a root and a tip. The continuous fiber blade may further includea blade attachment feature positioned at or adjacent to the root.Additionally, the component may include one or more platforms coupled tothe root of the continuous fiber blade. The platform(s) may include aplurality of chopped fibers. Additionally, the component may include athermoplastic polymer contained in both the continuous fiber blade andthe platform. The thermoplastic polymer may allow for the platform(s)containing the chopped fibers to be monolithically formed to thecontinuous fiber blade. Moreover, the continuous fiber blade andplatform(s) may be coupled together such that the continuous fiber bladeand platform(s) form a monolithic composite body. For instance, incertain embodiments, the platform(s) may be coupled to the bladeutilizing injection molding, or the platform(s) may be formed to theblade during a molding process of the platform(s). As such, thecomposite components of the present disclosure may reduce the processsteps involved in assembing multiple separate parts before orsimultaneously with attaching the component within the gas turbineengine. Further, a monolithic composite component, as described herein,may reduce the number of seals required within the engine, potentiallyincreasing the efficiency of the gas turbine engine. Moreover, theplatform(s) formed from chopped fibers may be more easily formed intocomplex shapes desired within the platform(s), while the continuousfibers of the blade may allow for greater strength to withstand theaerodynamic loads on the blade.

Referring now to the drawings, FIG. 1 illustrates a cross-sectional viewof one embodiment of a gas turbine engine 10 that may be utilized withinan aircraft in accordance with aspects of the present subject matter.More particularly, for the embodiment of FIG. 1, the gas turbine engine10 is a high-bypass turbofan jet engine, with the gas turbine engine 10being shown having a longitudinal or axial centerline axis 12 extendingtherethrough along an axial direction A for reference purposes. The gasturbine engine 10 further defines a radial direction R extendingperpendicular from the centerline 12. Further, a circumferentialdirection C (shown in/out of the page in FIG. 1) extends perpendicularto both the centerline 12 and the radial direction R. Although anexemplary turbofan embodiment is shown, it is anticipated that thepresent disclosure can be equally applicable to turbomachinery ingeneral, such as an open rotor, a turboshaft, turbojet, or a turbopropconfiguration, including marine and industrial turbine engines andauxiliary power units.

In general, the gas turbine engine 10 includes a core gas turbine engine(indicated generally by reference character 14) and a fan section 16positioned upstream thereof. The core engine 14 generally includes asubstantially tubular outer casing 18 that defines an annular inlet 20.In addition, the outer casing 18 may further enclose and support a lowpressure (LP) compressor 22 for increasing the pressure of the air thatenters the core engine 14 to a first pressure level. A multi-stage,axial-flow high pressure (HP) compressor 24 may then receive thepressurized air from the LP compressor 22 and further increase thepressure of such air. The pressurized air exiting the HP compressor 24may then flow to a combustor 26 within which fuel is injected into theflow of pressurized air, with the resulting mixture being combustedwithin the combustor 26. The high energy combustion products 60 aredirected from the combustor 26 along the hot gas path of the gas turbineengine 10 to a high pressure (HP) turbine 28 for driving the HPcompressor 24 via a high pressure (HP) shaft or spool 30, and then to alow pressure (LP) turbine 32 for driving the LP compressor 22 and fansection 16 via a low pressure (LP) drive shaft or spool 34 that isgenerally coaxial with HP shaft 30. After driving each of turbines 28and 32, the combustion products 60 may be expelled from the core engine14 via an exhaust nozzle 36 to provide propulsive jet thrust.

Additionally, as shown in FIG. 1, the fan section 16 of the gas turbineengine 10 generally includes a rotatable, axial-flow fan rotor 38configured to be surrounded by an annular fan casing 40. In particularembodiments, the LP shaft 34 may be connected directly to the fan rotor38 or rotor disk (not shown), such as in a direct-drive configuration.In alternative configurations, the LP shaft 34 may be connected to thefan rotor 38 via a speed reduction device 37 such as a reduction geargearbox in an indirect-drive or geared-drive configuration. Such speedreduction devices may be included between any suitable shafts/spoolswithin the gas turbine engine 10 as desired or required. Additionally,the fan rotor 38 and/or rotor disk may be enclosed or formed as part ofa fan hub 41.

It should be appreciated by those of ordinary skill in the art that thefan casing 40 may be configured to be supported relative to the coreengine 14 by a plurality of substantially radially-extending,circumferentially-spaced outlet guide vanes 42. As such, the fan casing40 may enclose the fan rotor 38 and its corresponding fan rotor blades(fan blades 44). Moreover, a downstream section 46 of the fan casing 40may extend over an outer portion of the core engine 14 so as to define asecondary, or by-pass, airflow conduit 48 that provides additionalpropulsive jet thrust.

During operation of the gas turbine engine 10, it should be appreciatedthat an initial airflow (indicated by arrow 50) may enter the gasturbine engine 10 through an associated inlet 52 of the fan casing 40.The air flow 50 then passes through the fan blades 44 and splits into afirst compressed air flow (indicated by arrow 54) that moves through theby-pass conduit 48 and a second compressed air flow (indicated by arrow56) which enters the LP compressor 22. The LP compressor 22 may includea plurality of rotor blades (LP rotor blades 45) enclosed by the outercasing 18. The pressure of the second compressed air flow 56 is thenincreased and enters the HP compressor 24 (as indicated by arrow 58).Additionally, the HP compressor 24 may include a plurality of rotorblades (HP rotor blades 47) enclosed by the outer casing 18. Aftermixing with fuel and being combusted within the combustor 26, thecombustion products 60 exit the combustor 26 and flow through the HPturbine 28. Thereafter, the combustion products 60 flow through the LPturbine 32 and exit the exhaust nozzle 36 to provide thrust for the gasturbine engine 10.

Referring now to FIG. 2, one embodiment of a monolithic compositecomponent 100 for a gas turbine engine 10 is illustrated in accordancewith aspects of the present subject matter. More particularly, FIG. 2illustrates two monolithic composite components 100 arrangedcircumferentially about the centerline 12 to form a stage 102. It shouldbe appreciated that monolithic, as used herein, means irreversiblycoupled together or formed together in order to create one indivisiblecomponent. Though two monolithic composite components 100 of the stage102 are illustrated in FIG. 2 for exemplary purposes, it should beappreciated that the stage 102 may include three or more monolithiccomposite components 100 such that the monolithic composite componentsare equally spaced about the centerline 12 in the circumferentialdirection C. Generally, as illustrated in FIG. 2, the monolithiccomposite component 100 will be described as a component of the LPcompressor 22 including LP rotor blade 45 as described generally inreference to FIG. 1. However, it should be appreciated that thefollowing description may be equally applicable to any other airfoil orblade of the gas turbine engine 10, such as a fan blade 44 or an HProtor blade 47. In particular embodiments, the monolithic compositecomponent 100 may include one of the first several HP rotor blades 47 ofthe HP compressor 24. However, in other embodiments, the monolithiccomposite component 100 may include a blade and/or airfoil of the HPturbine 28 or the LP turbine 32. Further, it should be appreciated that,in general, the disclosed monolithic composite component 100 maygenerally be utilized with any suitable gas turbine engine having anysuitable configuration.

FIG. 2 additionally illustrates a partial cutaway view of an examplecompressor rotor 104 of the LP compressor 22, according to at least someaspects of the present disclosure, in order to place the monolithiccomposite component 100 in an exemplary field of use. However, the rotormay be one of an HP compressor rotor, HP turbine rotor, LP turbinerotor, or the fan rotor 38 in another context. The compressor rotor 104may include the LP shaft 34, which may include a generally radiallyoutward facing, circumferentially oriented shaft attachment feature 106,such as, but not limited to, a circumferentially oriented dovetail slot108. Individual blades 110 may be releasably mounted to LP shaft 34 toextend radially outward, such as by engagement of a generallycircumferentially oriented blade attachment feature 112 with shaftattachment feature 106. For example, dovetail slot 108 may be configuredto slidably receive blade attachment feature 112 therein.

Referring now to FIG. 3, an exploded perspective view of an examplemonolithic composite component 100 is illustrated in accordance withaspects of the present subject matter. Particularly, FIG. 3 illustratesthe blade 110 and platforms 114, 116, according to at least some aspectsof the present disclosure. It should be appreciated that though theblade 110 and platforms 114, 116 are shown separated for illustrativepurposes in FIG. 3, the blade 110 and at least one of the platforms 114,116 may be inseperably coupled together to form the monolithic compositecomponent 100. The blade 110 may include a composite blade panel 118,which may include at least one of an airfoil 120 or blade attachmentfeature 112. As described in more detail below in regard to FIG. 5, theairfoil 120 and/or blade attachment feature 112 may be a continuousfiber airfoil and a continuous fiber attachment feature formed together.More particularly, the composite blade panel 118 may be a continuousfiber composite blade panel formed integrally. Airfoil 120 may bearranged such that its span 122 extends generally radially outward withrespect to the gas turbine engine 10 centerline 12 (FIGS. 1 and 2) froma root 142 to a tip 144. The blade 110 may define a pressure side 124and a suction side 126. More particularly, the airfoil 120 may includeat least one of a pressure side 124 or a suction side 126. Bladeattachment feature 112 may be disposed radially inward from the airfoil120 with respect to centerline 12 such that the attachment feature 112is positioned at or adjacent to the root 142 and/or may becircumferentially oriented with the centerline 12. Further, theplatform(s) 114, 116 may be inseperably coupled to the root 142 of theblade 110, such as at the blade attachment feature 112.

Blade attachment feature 112 may be generally shaped as a dovetail andmay include at least one of a neck 128, a forward lobe 130, or an aftlobe 132. Forward lobe 130 and/or aft lobe 132 may be radially inwardfrom the neck 128 with respect to the centerline 12 (FIG. 1). Bladeattachment feature 112 may have a substantially uniform cross-section inthe circumferential direction with respect to centerline 12. Platform114 may be disposed generally adjacent to the pressure side 124.Further, platform 116 may be disposed generally adjacent to the suctionside 126. Alternatively, platform 114 may be disposed generally adjacentto the pressure side 124 and platform 116 may be disposed generallyadjacent to the suction side 126. Platforms 114, 116 may extendgenerally circumferentially from blade panel 118 with respect to thecenterline 12 (FIG. 1). Further, the platform(s) 114, 116 may be coupledto the root 142 of the blade 110 (e.g., monolithically and irreversiblyformed to the blade 110) in order to form a monolithic composite body.As described in more detail in regard to FIG. 5, the platform(s) 114,116 may include a plurality of chopped fibers. Platforms 114, 116 mayinclude radially outward facing flowpath surfaces 134, 136,respectively, each of which may be generally shaped as a segment of acylinder. Platforms 114, 116 may include radially inwardly extendingattachment features 138, 140, respectively, which may be configured toreleasably engage shaft attachment feature 106 (FIG. 2). Attachmentfeatures 138, 140 of platforms 114, 116 may be constructed to havesubstantially the same circumferential cross-sections as bladeattachment feature 112. Further, in one arrangement, the platform 114 ofa first monolithic composite component 100 may define a butt joint 146with the platform 116 of an adjacent monolithic composite component 100in the circumferential direction C (see FIG. 2). Moreover, themonolithic composite components 100 may be in sealing engagement at oneor more butt joints 146 between adjacent monolithic composite components100 (e.g., adjacent monolithic composite components 100 in a stage 102).

Referring now to FIG. 4, an exploded perspective view of an alternativeexample of the monolithic composite component 100 is illustrated inaccordance with aspects of the present subject matter. Particularly,FIG. 4 illustrates the blade 110 and a split platform 148 according toat least some aspects of the present disclosure. It should beappreciated that though the blade 110 and split platform 148 are shownseparated for illustrative purposes in FIG. 4, the blade 110 and thesplit platform 148 may be inseperably coupled together to form themonolithic composite component 100. For instance, the split platform 148may be inseperably coupled to the root 142 of the blade 110, such as atthe blade attachment feature 112.

As shown in FIG. 4, the split platform 148 may extend generallycircumferentially from the blade panel 118 on both the pressure side 124and suction side 126 of the blade 110 with respect to the centerline 12(FIG. 1). For instance, the split platform 148 may include radiallyoutward facing pressure side flowpath surface 150 and suction sideflowpath surface 152, each of which may be generally shaped as a segmentof a cylinder. Further, the pressure and suction side flowpath surfaces150, 152 may define a notch 154 therebetween in order to receive theblade 110 and/or to be formed onto the blade 110. As described in moredetail in regard to FIG. 5, the split platform 148 may include aplurality of chopped fibers. The split platform 148 may include radiallyinwardly extending pressure side attachment feature 156 and suction sideattachment feature 158, each of which may be configured to releasablyengage shaft attachment feature 106 (FIG. 2). Attachment features 156,158 of the split platform 148 may be constructed to have substantiallythe same circumferential cross-sections as blade attachment feature 112.

Referring now to FIG. 5, another view of an exemplary monolithiccomposite component 100 is illustrated in accordance with aspects of thepresent disclosure. Particularly, FIG. 5 illustrates a partiallyexploded view where the platform 114 is separated from the blade 110while the platform 116 is shown monolithically formed to the blade 110.Though the monolithic composite component 100 of FIG. 5 is shownincluding the platforms 114, 116, in other embodiments the monolithiccomposite component 100 may include one of the platforms 114, 116, orany other suitable platform, such as split platform 148 of FIG. 4. Asshown, the blade 110 and/or the blade attachment feature 112 may includea plurality of continuous fibers 160 (several of which are shown forillustrative purposes). For instance, one or more of the continuousfibers 160 may extend from the root 142 to the tip 144. As such, blade110 may be a continuous fiber blade including a continuous fiber bladepanel 118. As additionally shown in FIG. 5, the platforms 114, 116 mayinclude a plurality of chopped fibers 162 (several of which are shownfor illustrative purposes). As further explained below, the monolithiccomposite component 100 may include a thermoplastic polymer 164 in boththe continuous fiber blade 110 and the chopped fiber platforms 114, 116.

Composite materials generally comprise a fibrous reinforcement materialembedded in matrix material, such as polymer or ceramic material. Thereinforcement material serves as a load-bearing constituent of thecomposite material, while the matrix of a composite material serves tobind the fibers together, and also acts as the medium by which anexternally applied stress is transmitted and distributed to the fibers.Many polymer matrix composite (PMC) materials are fabricated with theuse of prepreg, which is a fabric or unidirectional tape that isimpregnated with resin. Multiple layers of prepreg are stacked to theproper thickness and orientation for the part, and then the resin iscured and solidified to render a fiber reinforced composite part. Resinsfor matrix materials of PMCs can be generally classified as thermosetsor thermoplastics. Thermoplastic resins are generally categorized aspolymers that can be repeatedly softened and flowed when heated andhardened when sufficiently cooled due to physical rather than chemicalchanges. Notable example classes of thermoplastic resins include nylons,thermoplastic polyesters, polyaryletherketones, and polycarbonateresins. Specific example of high performance thermoplastic resins thathave been contemplated for use in aerospace applications include,polyetheretherketone (PEEK), polyetherketoneketone (PEKK),polyetherimide (PEI), polyaryletherketone (PAEK), and polyphenylenesulfide (PPS). In contrast, once fully cured into a hard rigid solid,thermoset resins do not undergo significant softening when heated, butinstead thermally decompose when sufficiently heated. Notable examplesof thermoset resins include epoxy, bismaleimide (BMI), and polyimideresins.

A variety of fibrous reinforcement materials have been used in PMCs, forexample, carbon (e.g., AS4), glass (e.g., S2), polymer (e.g., Kevlar®),ceramic (e.g. Nextel®) and metal fibers. Fibrous reinforcement materialscan be used in the form of relatively short chopped fibers, generallyless than two inches in length, and more preferably less than one inch,or long continuous fibers, the latter of which are often used to producea woven fabric or unidirectional tape. PMC materials can be produced bydispersing dry fibers into a mold, and then flowing matrix materialaround the reinforcement fibers, or by using prepreg as previouslydescribed.

Another complication is the type of reinforcement system required by PMCmaterials in aircraft engine applications. Generally, to achieve themechanical properties required for aircraft engine applications, partswould require the use of continuous fiber-reinforced PMC materials toachieve the high performance mechanical requirements (particularlystrength and fatigue properties) dictated by aircraft engineapplications (e.g., blades 110). However, the manufacturing processesinvolved in the fabrication of continuous fiber reinforcement compositeparts further complicate the ability to produce structures that havecomplex shapes. On the other hand, chopped fiber reinforcement systems,whether in a thermoplastic or thermoset resin matrix, are not idealsolutions for highly loaded parts due to their lower mechanicalperformance. However, it is possible to fabricate complex-shaped partswith chopped fiber material solutions with net-shaped molding methods,and therefore these material systems can be used for lightly-loadedsecondary structures and non-structural engine components (e.g., theplatforms 114, 116, and 148).

As engine performance continues to be pushed to limits, it is desirableto have parts of complex geometries that are capable of being highlyloaded to aid or improve such performance. Many times, these complexgeometries are non-structural features that help with, for example,aerodynamic performance. Therefore, taking a hybrid approach, amonolithic part is provided with hybrid fiber reinforcement to achievestructural loading yet providing for the complex shaped (lightly loaded)features, for example aero-features.

Referring back to the exemplary embodiment of FIG. 5, thermoplasticpolymer 164 may include a bonding layer 166 between the continuous fiberblade 110 and the platform(s) 114, 116 (only one bonding layer 166 isshown for clarity). In certain embodiments, the thermoplastic polymer164 may include one or more of PEKK, PEEK, PAEK, or PEI. In certainembodiments, thermoplastic polymer 164 may be the same within the blade110 and platform(s) 114, 116 in order to reduce thermal gradients withinthe parts of the monolithic composite component 100.

Further, in one embodiment, the continuous fiber blade 110 may beformed, at least in part, by molding of a continuous fiber thermoplasticcomposite. For instance, the continuous fiber blade 110 may beconstructed by laying up continuous fiber portions that are in a fabric,unidirectional tape, or braided architecture and the thermoplasticpolymer 164 within a mold to define the aerodynamic profile of the blade110. Further, the continuous fiber blade 110 may be formed of, fornon-limiting examples, unidirectional prepreg, woven fabric prepreg, abraided prepreg, or a dry reinforcement fiber with filaments or fibersof thermoplastic polymer. Additionally, the platform 114, 116, 148 maybe formed, at least in part, by at least one of compression molding orinjection molding of the plurality of chopped fibers 162. In at leastsome embodiments, the chopped fibers 162 may be included inunidirectional tape that has been chopped to a short fiber length. Thethermoplastic polymer 164 used in the chopped fiber unidirectional tapemay be the same thermoplastic polymer 164 that is used in the continuousfiber blade 110. The use of the same thermoplastic polymer 164 withinthe blade 110 and platforms 114, 116, 148 may allow the component to befabricated as the monolithic composite component 100 as depicted herein.

For example, the continuous fiber material may be continuous fibers 160of individual fibers or fiber tows arranged parallel (unidirectional)with the matrix material, or individual fibers or fiber tows arranged tohave multiple different orientations (e.g., multiple layers ofunidirectional fibers or fiber tows to form bi-axial or tri-axialarchitecture) within the matrix material, or individual fibers or fibertows, woven to form a mesh or fabric within the matrix material. Thefibers, tows, braids, meshes, or fabrics can be arranged to define asingle ply within the PMC or any suitable number of plies. Particularlysuitable continuous fiber reinforcement materials include carbon, glasspolymer, ceramic, and metal fibers.

According to one embodiment, the PMC material is defined in part byprepreg, which is a reinforcement material preimpregnated with a matrixmaterial, such as thermoplastic resin desired for the matrix material.Non-limiting examples of processes for producing thermoplastic prepregsinclude hot melt prepregging in which the fiber reinforcement materialis drawn through the molten bath of resin and powder prepregging inwhich a resin is deposited onto the fiber reinforcement material (forexample electrostatically) and then adhered to the fiber (for example,in an oven or with the assistance of heated rollers). The prepregs canbe in the form of unidirectional tapes or woven fabrics, which are thenstacked on top of one another to create the number of stacked pliesdesired for the part. According to an alternative option, instead ofusing a prepreg, with the use of thermoplastic polymers it is possibleto have a woven fabric that has, for example, dry carbon fiber woventogether with thermoplastic polymer fibers or filaments. Non-prepregbraided architectures can be made in a similar fashion. With thisapproach, it is possible to tailor the fiber volume of the part bydictating the relative concentrations of the thermoplastic fibers andreinforcement fibers that have been woven or braided together.Additionally, different types of reinforcement fibers can be braided orwoven together in various concentrations to tailor the properties of thepart. For example, glass fiber, carbon fiber, and thermoplastic fibercould all be woven together in various concentrations to tailor theproperties of the part. The carbon fiber provides the strength of thesystem, the glass may be incorporated to enhance the impact properties,which is a design characteristic for parts located near the inlet of theengine, and the thermoplastic fibers are the matrix that will be flowedto bind the reinforcement fibers.

The ply stack may next undergo a consolidation operation, in which heatand pressure are applied to the ply stack to flow the resin andconsolidate the ply stack into the part. In addition to creating partsusing prepreg, an alternative approach is to lay-up dry fabric in asuitably shaped mold cavity and then infuse the dry fabric with moltenresin. For instance, PMC materials can be produced by dispersing dryfibers into a mold, and then flowing matrix material around thereinforcement fibers.

According to the instant embodiment, the continuous fiber blade 110 orchopped fiber platform(s) 114, 116, 148 may be loaded into compressionmolds. Within these molds may be cavities corresponding to the shape ofblade 110 or platform 114, 116, 148 respectively. Additionally, theplatform(s) 114, 116, 148 may be coupled to the continuous fiber blade110 via injection molding at an interface 168 between the continuousfiber blade 110 and the platform(s) 114, 116, 148 in order to form thebonding layer 166 and the monolithic composite component 100 as shown inFIG. 5. In another embodiment, the platform(s) 114, 116, 148 may becoupled to the continuous fiber blade 110 simultaneously with themolding of the platform(s) 114, 116, 148. For instance, the platform(s)114, 116, 148 may be directly molded onto the continuous fiber blade 110as to form the bonding layer(s) 166 at the interface(s) 168 ofmonolithic composite component 100.

Referring now to FIG. 6, a flow diagram of one embodiment of a method200 of forming a monolithic composite component for a gas turbine engineis illustrated in accordance with aspects of the present disclosure. Ingeneral, the method 200 will be described herein with reference to thegas turbine engine 10 and monolithic composite component 100 describedabove in reference to FIGS. 1-5. However, it should be appreciated bythose of ordinary skill in the art that the disclosed method 200 maygenerally be utilized to form any suitable monolithic compositecomponent in connection with any gas turbine engine having any suitableconfiguration. In addition, although FIG. 6 depicts steps performed in aparticular order for purposes of illustration and discussion, themethods discussed herein are not limited to any particular order orarrangement. One skilled in the art, using the disclosures providedherein, will appreciate that various steps of the methods disclosedherein can be omitted, rearranged, combined, and/or adapted in variousways without deviating from the scope of the present disclosure.

As depicted in FIG. 6, the method 200 may include (202) molding acontinuous fiber thermoplastic composite into the continuous fiber blade110 including the airfoil 120 extending radially outward from the root142 to the tip 144 and the blade attachment feature 112 positioned at oradjacent to the root 142. The method 200 may additionally include (204)forming a plurality of chopped fibers 162 into the platform (e.g., anyof the platforms 114, 116, 148) containing the thermoplastic polymer164. In one embodiment, forming the plurality of chopped fibers 162 intothe platform may include at least one of compression molding orinjection molding of the chopped fibers 162.

Further, the method 200 may include (206) coupling the platform to theroot 142 of the continuous fiber blade 110 such that the platform andcontinuous fiber blade 110 form the monolithic composite component 100.In one particular embodiment, coupling the platform to the root 142 ofthe continuous fiber blade 110 may include utilizing injection moldingat the interface 168 between the platform and the continuous fiber blade110. In an additional and/or alternative embodiment, coupling theplatform to the root 142 of the continuous fiber blade 110 may includesimultaneously coupling the platform to the continuous fiber blade 110while molding the platform.

This written description uses exemplary embodiments to disclose theinvention, including the best mode, and also to enable any personskilled in the art to practice the invention, including making and usingany devices or systems and performing any incorporated methods. Thepatentable scope of the invention is defined by the claims, and mayinclude other examples that occur to those skilled in the art. Suchother examples are intended to be within the scope of the claims if theyinclude structural elements that do not differ from the literal languageof the claims, or if they include equivalent structural elements withinsubstantial differences from the literal languages of the claims.

What is claimed is:
 1. A component for a gas turbine engine, thecomponent comprising: a continuous fiber blade including an airfoilextending radially between a root and a tip and a blade attachmentfeature positioned at or adjacent to the root; a platform coupled to theroot of the continuous fiber blade, the platform including a pluralityof chopped fibers; and a thermoplastic polymer contained in both thecontinuous fiber blade and the platform, wherein the continuous fiberblade and platform are coupled together such that the continuous fiberblade and platform form a monolithic composite body.
 2. The component ofclaim 1, wherein the continuous fiber blade is formed, at least in part,by molding of a continuous fiber thermoplastic composite.
 3. Thecomponent of claim 1, wherein the platform is formed, at least in part,by at least one of compression molding or injection molding of theplurality of chopped fibers.
 4. The component of claim 3, wherein theplatform is coupled to the continuous fiber blade via injection moldingat an interface between the platform and the continuous fiber blade. 5.The component of claim 3, wherein the platform is coupled to thecontinuous fiber blade simultaneously with the molding of the platform.6. The component of claim 1, wherein the thermoplastic polymer includesa bonding layer between the continuous fiber blade and the platform. 7.The component of claim 1, wherein the continuous fiber blade defines apressure side and a suction side, and wherein the platform is coupled tothe pressure side or suction side of the continuous fiber blade.
 8. Thecomponent of claim 1, wherein the continuous fiber blade defines apressure side and a suction side, and wherein the platform comprises twoplatforms, a first platform coupled to the pressure side of thecontinuous fiber blade, and a second platform coupled to the suctionside of the continuous fiber blade.
 9. The component of claim 1, whereinthe platform comprises a split platform defining a notch such that thecontinuous fiber blade is received within the notch and coupled to thesplit platform at the notch.
 10. The component of claim 1, wherein thethermoplastic polymer comprises at least one of PEKK, PEEK, PAEK, orPEI.
 11. A gas turbine engine defining a centerline, the gas turbineengine comprising: an engine shaft extending along the centerline; acompressor attached to the engine shaft and extending radially about thecenterline; a combustor positioned downstream of the compressor toreceive a compressed fluid therefrom; a turbine mounted on the engineshaft downstream of the combustor to provide a rotational force to thecompressor; and a monolithic composite component connected to the engineshaft, the monolithic composite component comprising: a continuous fiberblade including an airfoil extending radially outward from a root to atip and a blade attachment feature positioned at or adjacent to theroot; a platform coupled to the root of the continuous fiber blade, theplatform including a plurality of chopped fibers; and a thermoplasticpolymer contained in both the continuous fiber blade and the platform,wherein the continuous fiber blade and platform are coupled togethersuch that the continuous fiber blade and platform form a monolithiccomposite body.
 12. The gas turbine engine of claim 11, wherein thethermoplastic polymer includes a bonding layer between the continuousfiber blade and the platform.
 13. The gas turbine engine of claim 11,wherein the continuous fiber blade defines a pressure side and a suctionside, and wherein the platform is coupled to the pressure side orsuction side of the continuous fiber blade.
 14. The gas turbine engineof claim 11, wherein the platform comprises a split platform defining anotch such that the continuous fiber blade is received within the notchand coupled to the split platform at the notch.
 15. The gas turbineengine of claim 11, wherein the gas turbine engine includes a pluralityof monolithic composite components, wherein a portion of the monolithiccomposite components are arranged circumferentially about the centerlineto form a stage.
 16. The gas turbine engine of claim 15, wherein theplatforms of each of the plurality of monolithic composite componentsextend at least partially in a circumferential direction relative to thecenterline, and wherein the platform of at least two adjacent monolithiccomposite components of the portion of the monolithic compositecomponents define a butt joint therebetween in the circumferentialdirection.
 17. A method of forming a monolithic composite component fora gas turbine engine, the method comprising: molding a continuous fiberthermoplastic composite into a continuous fiber blade including anairfoil extending radially outward from a root to a tip and a bladeattachment feature positioned at or adjacent to the root; forming aplurality of chopped fibers into a platform containing a thermoplasticpolymer; and coupling the platform to the root of the continuous fiberblade such that the platform and continuous fiber blade form themonolithic composite component.
 18. The method of claim 17, whereinforming the plurality of chopped fibers into the platform comprises atleast one of compression molding or injection molding of the choppedfibers.
 19. The method of claim 17, wherein coupling the platform to theroot of the continuous fiber blade comprises utilizing injection moldingat an interface between the platform and the continuous fiber blade. 20.The method of claim 18, wherein coupling the platform to the root of thecontinuous fiber blade comprises simultaneously coupling the platform tothe continuous fiber blade while molding the platform.